Which of the following statements is NOT true?

The statement that "Dispersion does not affect a highly focused beam of energy" is not true because dispersion is a phenomenon that can influence all forms of wave energy, regardless of their focus. Dispersion refers to the way that different frequencies of a signal travel at different speeds. Even in a highly focused beam, variations in frequency can lead to the spreading out of the signal over distance, resulting in potential degradation of clarity and performance. This spreading can cause issues such as signal distortion and loss of resolution, particularly over long distances.

In contrast, other statements hold true: dispersion does indeed affect the clarity of signals as varying frequencies can lead to time delays and distortion; dispersion can be controlled by frequency, as different wavelengths interact with media in different ways; and it can significantly affect performance, particularly in communications and radar technologies, where clear signal transmission is critical.